add example how to use rtcd

Just use vp8_sixtap_predict as example but have not
implemented it actually.

Test:
$ CROSS=riscv64-unknown-linux-gnu- ../libvpx/configure --target=riscv64-linux-gcc
$ make

Check if vp8_sixtap_predict functions have been replaced with those
suffixed with "_rvv":
$ riscv64-unknown-linux-gnu-nm ./vp8/decoder/decodeframe.c.o | grep vp8_sixtap_predict16x16
                 U vp8_sixtap_predict16x16_rvv

Check if vp8_sixtap_predictMxN_rvv work.
$ qemu-riscv64 -L $SYSROOT_RV64  ./build-test/test_libvpx --gtest_filter="RVV/SixtapPredictTest.TestWithPresetData/*"
You should see print log output such as: "--> vp8_sixtap_predict4x4_rvv"
"FAILED" is expected due to we have not implemented the actual
algorithm.

Signed-off-by: Wang Chen <wangchen20@iscas.ac.cn>
Co-authored-by: sun min <sunmin89@outlook.com>

5 files changed, 83 insertions, 4 deletions

diff --git a/build/make/Makefile b/build/make/Makefile
index 65ac2290c..427330fd8 100644
--- a/build/make/Makefile
+++ b/build/make/Makefile
@@ -157,6 +157,10 @@ $(BUILD_PFX)%_lsx.c.o:  CFLAGS += -mlsx
 $(BUILD_PFX)%_lasx.c.d: CFLAGS += -mlasx
 $(BUILD_PFX)%_lasx.c.o: CFLAGS += -mlasx
 
+# RISCV
+$(BUILD_PFX)%_rvv.c.d:  CFLAGS += -march=rv64gcv
+$(BUILD_PFX)%_rvv.c.o:  CFLAGS += -march=rv64gcv
+
 $(BUILD_PFX)%.c.d: %.c
 	$(if $(quiet),@echo "    [DEP] $@")
 	$(qexec)mkdir -p $(dir $@)
diff --git a/test/predict_test.cc b/test/predict_test.cc
index 747297057..d686a9161 100644
--- a/test/predict_test.cc
+++ b/test/predict_test.cc
@@ -350,6 +350,15 @@ INSTANTIATE_TEST_SUITE_P(
                       make_tuple(4, 4, &vp8_sixtap_predict4x4_mmi)));
 #endif
 
+#if HAVE_RVV
+INSTANTIATE_TEST_SUITE_P(
+    RVV, SixtapPredictTest,
+    ::testing::Values(make_tuple(16, 16, &vp8_sixtap_predict16x16_rvv),
+                      make_tuple(8, 8, &vp8_sixtap_predict8x8_rvv),
+                      make_tuple(8, 4, &vp8_sixtap_predict8x4_rvv),
+                      make_tuple(4, 4, &vp8_sixtap_predict4x4_rvv)));
+#endif
+
 class BilinearPredictTest : public PredictTestBase {};
 
 TEST_P(BilinearPredictTest, TestWithRandomData) {
diff --git a/vp8/common/riscv/sixtap_predict_rvv.c b/vp8/common/riscv/sixtap_predict_rvv.c
new file mode 100644
index 000000000..0345d026e
--- /dev/null
+++ b/vp8/common/riscv/sixtap_predict_rvv.c
@@ -0,0 +1,63 @@
+#include <riscv_vector.h>
+#include <stdio.h>
+#include "./vpx_config.h"
+#include "./vp8_rtcd.h"
+
+#define UNUSED(x) (void)(x)
+
+void vp8_sixtap_predict4x4_rvv(unsigned char *src_ptr, int src_pixels_per_line,
+                                int xoffset, int yoffset,
+                                unsigned char *dst_ptr, int dst_pitch)
+{
+  UNUSED(src_ptr);
+  UNUSED(src_pixels_per_line);
+  UNUSED(xoffset);
+  UNUSED(yoffset);
+  UNUSED(dst_ptr);
+  UNUSED(dst_pitch);
+
+  printf("--> vp8_sixtap_predict4x4_rvv\n");
+}
+
+void vp8_sixtap_predict8x4_rvv(unsigned char *src_ptr, int src_pixels_per_line,
+                                int xoffset, int yoffset,
+                                unsigned char *dst_ptr, int dst_pitch)
+{
+  UNUSED(src_ptr);
+  UNUSED(src_pixels_per_line);
+  UNUSED(xoffset);
+  UNUSED(yoffset);
+  UNUSED(dst_ptr);
+  UNUSED(dst_pitch);
+
+  printf("--> vp8_sixtap_predict8x4_rvv\n");
+}
+
+void vp8_sixtap_predict8x8_rvv(unsigned char *src_ptr, int src_pixels_per_line,
+                                int xoffset, int yoffset,
+                                unsigned char *dst_ptr, int dst_pitch)
+{
+  UNUSED(src_ptr);
+  UNUSED(src_pixels_per_line);
+  UNUSED(xoffset);
+  UNUSED(yoffset);
+  UNUSED(dst_ptr);
+  UNUSED(dst_pitch);
+
+  printf("--> vp8_sixtap_predict8x8_rvv\n");
+}
+
+void vp8_sixtap_predict16x16_rvv(unsigned char *src_ptr,
+                                  int src_pixels_per_line, int xoffset,
+                                  int yoffset, unsigned char *dst_ptr,
+                                  int dst_pitch)
+{
+  UNUSED(src_ptr);
+  UNUSED(src_pixels_per_line);
+  UNUSED(xoffset);
+  UNUSED(yoffset);
+  UNUSED(dst_ptr);
+  UNUSED(dst_pitch);
+
+  printf("--> vp8_sixtap_predict16x16_rvv\n");
+}
diff --git a/vp8/common/rtcd_defs.pl b/vp8/common/rtcd_defs.pl
index 739a61284..3831a3c35 100644
--- a/vp8/common/rtcd_defs.pl
+++ b/vp8/common/rtcd_defs.pl
@@ -146,16 +146,16 @@ if (vpx_config("CONFIG_POSTPROC") eq "yes") {
 # Subpixel
 #
 add_proto qw/void vp8_sixtap_predict16x16/, "unsigned char *src_ptr, int src_pixels_per_line, int xoffset, int yoffset, unsigned char *dst_ptr, int dst_pitch";
-specialize qw/vp8_sixtap_predict16x16 sse2 ssse3 neon dspr2 msa mmi lsx/;
+specialize qw/vp8_sixtap_predict16x16 sse2 ssse3 neon dspr2 msa mmi lsx rvv/;
 
 add_proto qw/void vp8_sixtap_predict8x8/, "unsigned char *src_ptr, int src_pixels_per_line, int xoffset, int yoffset, unsigned char *dst_ptr, int dst_pitch";
-specialize qw/vp8_sixtap_predict8x8 sse2 ssse3 neon dspr2 msa mmi lsx/;
+specialize qw/vp8_sixtap_predict8x8 sse2 ssse3 neon dspr2 msa mmi lsx rvv/;
 
 add_proto qw/void vp8_sixtap_predict8x4/, "unsigned char *src_ptr, int src_pixels_per_line, int xoffset, int yoffset, unsigned char *dst_ptr, int dst_pitch";
-specialize qw/vp8_sixtap_predict8x4 sse2 ssse3 neon dspr2 msa mmi/;
+specialize qw/vp8_sixtap_predict8x4 sse2 ssse3 neon dspr2 msa mmi rvv/;
 
 add_proto qw/void vp8_sixtap_predict4x4/, "unsigned char *src_ptr, int src_pixels_per_line, int xoffset, int yoffset, unsigned char *dst_ptr, int dst_pitch";
-specialize qw/vp8_sixtap_predict4x4 mmx ssse3 neon dspr2 msa mmi lsx/;
+specialize qw/vp8_sixtap_predict4x4 mmx ssse3 neon dspr2 msa mmi lsx rvv/;
 
 add_proto qw/void vp8_bilinear_predict16x16/, "unsigned char *src_ptr, int src_pixels_per_line, int xoffset, int yoffset, unsigned char *dst_ptr, int dst_pitch";
 specialize qw/vp8_bilinear_predict16x16 sse2 ssse3 neon msa/;
diff --git a/vp8/vp8_common.mk b/vp8/vp8_common.mk
index d485965d3..54bb5eadb 100644
--- a/vp8/vp8_common.mk
+++ b/vp8/vp8_common.mk
@@ -146,4 +146,7 @@ VP8_COMMON_SRCS-$(HAVE_NEON)  += common/arm/neon/mbloopfilter_neon.c
 VP8_COMMON_SRCS-$(HAVE_NEON)  += common/arm/neon/shortidct4x4llm_neon.c
 VP8_COMMON_SRCS-$(HAVE_NEON)  += common/arm/neon/sixtappredict_neon.c
 
+# common (rvv intrinsics)
+VP8_COMMON_SRCS-$(HAVE_RVV) += common/riscv/sixtap_predict_rvv.c
+
 $(eval $(call rtcd_h_template,vp8_rtcd,vp8/common/rtcd_defs.pl))